VRO using small amount of oil, 70hp-97

[imported_Jimbo]

Hello,

I have just finished breaking in a re-bored 3-cyl Johnson 70-97, about 10 hours with 2% extra oil in the fuel. I have roughly gone through 30 gallons of fuel in that time. I marked the oil-level in the tank before putting the boat in the water. It should roughly have used half a gallon of oil for that fuel, am I right? It has definately not used that much, perhaps half if that... Right now i will continue running 1-1.5% extra oil in the fuel before I verify the operation. Thal oil-alarm does not go off (horn works), and last year, before the re-bore it seemed to use the correct amount of oil... Any ideas of what can be the problem?

Are there any way of verifying the oil-consumption without running the motor in gear at 1500rpm as my clymer manual suggests?

After reading http://continuouswave.com/whaler/reference/VRO.html it seems unlikely that the VRO is not working without any alarm...

Thanks,

Jimbo

PS IT should be ok to mix different oils in the WRO-tank as long as they follow the TC-W3 spec right? Still have 1/4 of the tank filled with unknown oil-brand from previous owner...

 

[tashasdaddy]

Re: VRO using small amount of oil, 70hp-97

mixing should be fine, i would mix my fuel 50:1 also, seeing you are in break in. and not sure you are getting vro correct. yes should have used 1 1/2 gallons. 68ounces. i think i would disconnect the oil line at the pump. and prime the oil line until you have good oil, with out air, to be sure you have oil to the pump.

 

[clemsonfor]

Re: VRO using small amount of oil, 70hp-97

if unsure if vro is working on a rebuilt motor please mix 50:1 in the tank untill it is confirmed!! you need double oil or so for break in anyhow like TD said

 

[imported_Jimbo]

Re: VRO using small amount of oil, 70hp-97

Thanks for the replies,

I have been mixing just over 2% in the fuel for more than 10 hours (3 hours in the end of last season and 7 this year), and now I consider the engine to be broken in. As I wrote, the VRO have used oil during this period but I don?t think it is at the rate its supphosed to be. Before the rebuild last year it seemed to use the correct amount of oil (engine seized on the mid cylinder due to blocking of the main jet, the other cylinders were fine, and well lubricated when the engine was opend). I will top up the VRO and fuel tanks tomorrow and go for a spin, then tip them up again to se the ratio...

Any thoughts of what could be the error, considering there is no alarm engaged. BTW the engine runs great after the rebuild...

I will keep mixing the fuel until I?m sure what is going on with the VRO.

Thanks,

Jimbo

 

[clemsonfor]

Re: VRO using small amount of oil, 70hp-97

mix in your fuel tank to 50:1 the extra oil will not hurt, but if your vro turns out not to be oiling enough it will be to late and all that lean running will be on your new outboard.

One thing you may not be thinking about, and im no vro expert just what i have read, is that is a variable ratio, if your idling for say 5 gals you wont use the same oil that you would if you burned 5 gals at WOT. So i gues what im saying is it depends on what you do with the boat the exact oil you should use. I have heard some say at idle the ratio of vro is like 100:1 and mid throttle is like 75:1? and WOT is in the 50:1 range?

just my thoughts

and you can always disconnect and mix the fuel yourself and not worry about it!

-nate

 

[ezeke]

Re: VRO using small amount of oil, 70hp-97

The VRO system was discontinued after 1992 and OMS, which averages about 60:1 mix, according to your above referenced article[1], was used after that. You should have used (30 X 128)/60 = 64ounces or 1/2 gallon from the Oil Tank.

1"Since 1993, the VRO is actually called an oil metering system (OMS). The ratio averages about 60:1, slightly leaner at idle and slightly richer at full throttle. The older pumps idled between 150:1 (prior to 1990) and 100:1 (1990-1992), then richened up to 50:1 as the engine load increased. They are recognized by the brown fuel outlet fitting and/or a wiring harness attached to the alarm module."

1 http://continuouswave.com/whaler/reference/VRO.html